Less than a week after Microsoft began taking reservation orders for its 128GB Surface Pro tablet, the company on Thursday again slapped a sold-out sign on its website.

Yesterday afternoon, Microsoft's online store displayed "Out of stock" and refused to accept orders for that configuration. The message remained in place Friday.

The new shortage makes Microsoft's blog post of Feb. 15 seem prescient. Then, as the company announced it would start taking orders for the 128GB Surface Pro, it warned customers that, "Once inventory is depleted, the system will show as 'out of stock' until new inventory is available to ship."

That's exactly what it did.

The Surface Pro has had an up-down-up-down history, brief as it's been.

Microsoft started selling the 128GB Surface Pro on Feb. 9 for $999, but within hours supplies dried up. Customers were furious, frustrated at coming up empty in their searches for the tablet, and took it out on Microsoft in scathing comments on the company's own blog and others.

A week ago, Microsoft reopened online ordering, telling customers that their tablet would ship on or before March 1. Rather than simply extend that shipping date into the future as supplied dwindled -- a practice most other vendors, including Apple, take when orders exceed demand -- Microsoft shut down orders completely.

The $899 64GB Surface Pro, which has been derided by some for having only about 30GB of storage space for customer content and apps, has remained available throughout the sell-outs of its sibling.

The on-again, off-again 128GB Surface Pro availability shows that Microsoft seriously underestimated demand for the tablet-becomes-an-ultrabook, said Ezra Gottheil, an analyst with Technology Business Research.

"It's beginning to look like this isn't a problem with building up enough inventory for the launch, but that Microsoft underestimated demand," said Gottheil, countering those who two weeks ago accused Microsoft of a marketing gimmick by purposefully holding back the tablet.

"Surface was first to be an inspiration to the OEMs, a marketing device to increase awareness of Windows 8, a challenge to the OEMs to come up with better designs," said Gottheil, echoing pundits' takes of mid-2012 when Microsoft surprised the technology industry with tablets of its own design that it would sell itself.